# Boxplots Example -- Create a variety of boxplots
# under a variety of conditions.

# Read data from UCLA website.
hsb2 <- read.table('http://www.ats.ucla.edu/stat/r/modules/hsb2.csv', 
   header=T, sep=",")
attach(hsb2)

# Send graphs to file.
pdf("boxplots.pdf")

# Create boxplots.
boxplot(write, main="Boxplots Example: Boxplot 1")

boxplot(write, xlab="Writing Score", boxwex=.4, col="lightblue",
   main="Boxplots Example: Boxplot 2")

boxplot(write ~ ses, main="Boxplots Example: Boxplot 3")

seslab <- as.vector(c("low","medium", "high"))
sesf <- factor(ses, label=seslab)
boxplot(write ~ sesf, xlab="write by ses", 
   main="Boxplots Example: Boxplot 4")

boxplot(write ~ sesf, xlab="write by ses", 
        boxwex=.2, notch = TRUE, 
        col = "lightblue", main="Boxplots Example: Boxplot 5")

# Use two factors
boxplot(write ~ female + ses, xlab="write by female and ses", 
        boxwex=0.2)

dev.off( )